Seismic performance of resilient beam-column connection using replaceable stiffener angle steel

An innovative performance-recoverable beam-column connection was proposed to achieve the restoration of structural functionality after earthquakes, which had recently emerged as an important issue facing the structural engineering profession. The beam-column joint was assembled using a connector and a web friction device, post tensioned strands and replaceable stiffener angel steels were also employed to provide a self-centering capacity and a replaceable capacity, respectively. Cyclic tests were conducted on five groups of specimens to explore the seismic behavior of the proposed connection, and the effects of welding stiffener for angle steel, replacing stiffener angle steel, different connector flanget thickness and angle steel thickness on the seismic performance were investigated. During the test process, the proposed connection performed an excellent seismic behavior, and the damage could be concentrated in the stiffener angle steel when the connector flange adopted a reasonable thickness. The results indicated that welding stiffener for angle steel could substantially improve the initial stiffness and energy dissipation of the connection joint. Increasing the connector flange thickness could effectively reduce the plastic deformation and the degree of outward buckling to cut down the prestress loss of the post tensioned strands. The replacement of stiffener angle steels after the earthquake could realize a certain degree of seismic performance recovery of the connection, which was a fast low-cost repair method. In addition, a novel design philosophy of “elastic under minor earthquake, self-centering under moderate earthquake and replaceable under major earthquake” could be realized well by rational design, which could provide a good reference for practical engineering. Based on the test results, a moment calculation method, which could distinguish the gap opening was proposed, and the calculated results agreed well with the experimental results. However, the proposed connection had only been tested under a bending situation including shear, in-depth study of the combined force behavior should be researched in the further.